aclocal: declare function prototypes, do not use '&' in function calls

aclocal: declare function prototypes, do not use '&' in function calls

This change will also fix automake bug#11543 (from a report by Matt
Burgess).

* aclocal.in: Declare prototypes for almost all functions early, before
any actual function definition (but omit the prototype for the dynamically
generated '&search' function).  Add prototypes to any function definition.
Remove '&' from function invocations (i.e., simply use "func(ARGS..)"
instead of "&func(ARGS...)").
* THANKS, NEWS: Update.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>